Cut the puff pastry into 16 triangles (first cut into 4, then 8, then 16, like slicing a cake)

Spread the cream cheese over the puff pastry. Peel and finely chop the shallot and chives. Sprinkle them over the cream cheese.

Cut the smoked salmon into strips about 1/4 inch (about 0.5 cm) wide, matching the width of the triangles. Place a strip on the wide end of each triangle, then roll up to form croissants. Place them on a baking sheet.

Beat the egg and brush it over the croissants. Sprinkle with sesame seeds (you can use a mix of black and white seeds if you like).

Bake at 410°F (210°C) for 15 minutes.